I just recently purchased a 1994 B3000 SE with just over 300,000 miles. It runs great but from time-to-time the check engine light will come on for a few seconds then go out. Seems to always be at random and mostly when first started and last no more than a few seconds. I put a code reader on it and got nothing. I was told just to replace all the sensors but that can be over $100 or more and may not fix the problem.

 

Someone is giving you bad advise. Replacing all sensors? Did this kid have acne?

I suggest you do the basics first: clean the MAF sensor and the throttle body with specific cleaners. CRC MAF sensor cleaner and CRC Throttle body cleaner. Clean the EGR valve and EGR ports.
Replace plugs, wires and coil pack or distributor cap and rotor if so equipped.
Replace the PCV valve.
Check for vacuum leaks.
Make sure the gas cap is on correctly and inspect or replace the O-ring at the gas cap.
There is a good chance that one of these measures will end the random CEL.

 

Vacuum may be a good place to start. I have found 2 places that look like there should be a rigid vacuum line but I really don't think the 2 places connect together but can't find anywhere where they should connect.

 

honestly, I am not familiar with this engine. There should be a vacuum diagram under the hood or you may find one using google image search. The B series truck is a re-badged Ford Ranger so you may search under the ranger name as well. "The Ranger Station" is a dedicated forum for these.

all the best.

 

May have been a vacuum leak. I did a search on the engine I have and found a picture that shows the vacuum the 2 pictures I posted where there circles are should be connected. Since I replaced the vacuum line the engine light hasn't come on. The vacuum diagram under my hood was hard to read and I wouldn't have known where this line would have been on the engine. Maybe I should find that picture again or just post a picture of what I fixed.

Thanks...

 

Nice job! You should be good.